In which of the following scales of measurement is ranking of observations not possible?

Ranking of observations is not possible on the nominal scale, which only names categories.

Nominal values differ in kind, carrying no order among them.

The ordinal scale, by contrast, does rank observations.

The interval scale ranks values and adds equal intervals between them.

The ratio scale ranks, has equal intervals and a true absolute zero.

Gender, religion and blood group are typical nominal variables.